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2.3.1 Riprap <br />Riprap along riverbanks shall be designed in accordance with <br />the provision of the USA(Tt except that the banks along the <br />rivers and streams protected with riprap or riprap with vegeta- <br />tion are to be sloped at no steeper than 2.SH:lV up to the <br />2-year flood level and 4H:1V above the 2-year flood level. All <br />riprap sizing is to be based on the velocities associated with <br />the 100-year event. The rock will be extended vertically <br />downward beyond the tce of the slope at least 5 feet below the <br />channel thalweg (Phase B Master Plan low flow channel bottom). <br />All type VL and L riprap shall be buried and revegetated as re- <br />quired by the USDQI. Larger rock may be buried at the discre- <br />tion of the owner. if rock is to be buried, the provisions of <br />Sections 2.3.2 - Riprap with Vegetation shall be followed. <br />Typical rock and bedding placement details are illustrated on <br />Figure 2.2. <br />2.3.2 Riprap with Vegetation <br />Rock used in conjunction with vegetation shall be sized in <br />accordance with the requirements of the USDCat. The velocities <br />associated with the 100-year flood are to be used for determin- <br />ing rock sizes. The sizing of riprap shall be in accordance <br />with Section 2.3.1 - Riprap. <br />Soil, seed and rock shall be mixed into one homogeneous mixture <br />with all voids filled. Seed mixtures used in this mass are to <br />conform with the (sidelines for Vegetation; however, they <br />should also include dormant willow slash to encourage the <br />growth of willow shrubbery in addition to native grasses as <br />required. willow slash shall be included at a rate of 20 <br />pounds of dormant willow slash per 100 pounds of live seed of <br />grass mixture. The combination of seed, willow slash, soil, <br />UDSFCD GRAVEL GUIDELINES 12/17/87 <br />2-8 <br />